<!DOCTYPE html>
<html>
  <head>
    <script>
      function change() {
        return "<html><body>change</body></html>";
      }
      function change2() {
        return "<html><body>change2</body></html>";
      }
    </script>
  </head>
  <body>
    <iframe src="javascript:parent.change()"></iframe>
  </body>
</html>
